docs: def _corrupt(self, data, dpos):
          """Corruption from SHA1 core."""
          ws = list(self._BLK_BE.unpack_from(data, dpos))
          for t in range(16, 80):
              tmp = ws[(t - 3) & 15] ^ ws[(t - 8) & 15] ^ ws[(t - 14) & 15] ^ ws[(t - 16) & 15]
              ws[t & 15] = ((tmp << 1) | (tmp >> (32 - 1))) & 0xFFFFFFFF
          self._BLK_LE.pack_into(data, dpos, *ws)